By studying the human body’s anatomy and physiology, we will learn that it is divided into many cavities separated by membranes, that they not only compartmentalize our bodily fluids and organs but also protect them. The two largest cavities are the dorsal cavity and ventral cavity.
Dorsal Cavity
The Dorsal cavity involves the spinal cavities and the cranial cavities. It also contains nerve plexus and a single nerve that exits the spinal column. This cavity is filled with fluid that houses and surrounds our spinal cord and the brain. But, this fluid is completely separated from the bloodstream, also known as the blood-brain barrier.
The Blood-Brain barrier separates the brain from the blood via the dorsal cavity and the epithelial cells. It is significant in protecting the brain from infections brought about by pathogens and circulating toxins. It is also vital in supplying nutrients that our brain needs.
There are three meninges that line the dorsal cavity: the pia mater, dura mater, and arachnoid mater. They are the membranes that enclose the spinal cord and the brain.
Cranial Cavity
Commonly referred to as the “space between the skull,” it is formed by neurocranium or the eight cranial bones: the occipital bone, two parietal bones, frontal bone, two temporal bones, ethmoid and sphenoid bones. It also contains protective membranes called meninges surrounding the brain to protect it from damage during head trauma.
Spinal Cavity
The posterior part of the dorsal cavity is commonly known as the vertebral cavity or vertebral canal. Considered the most narrow cavity amongst all other body cavities and encases the spinal cord, the fluid-filled spaces in between, and the meninges of the spinal cord.
This cavity ends at the L2 level of the vertebral column, where the “cauda equina” is located. It also is the area where the spinal nerve and cord roots out to the second and 5th levels of the vertebrae.
Functions of the Dorsal Cavity
The dorsal cavity is responsible for the awareness and sensations of the central nervous system. The nerves found in the spinal cord travel to the different parts of the body. The CNS regulates body organ movement and control. It is also a vessel that communicates stimulus from the brain that causes the body to respond.
The dorsal cavity functions like any other cavity. It provides a cushion to protect the brain and the spinal cord from impacts and damage. Both are vital organs of the body that have delicate nervous tissues that are damaged easily. The fluid that fills the space serves as a buffer that is pressurized and pushes back whenever outside forces push against the organs in the dorsal cavity.
The cerebrospinal fluid is a clear liquid produced by our brain’s special cells. It surrounds the spinal cord and the brain, and its main function is to act as a cushion and shock-proof protection. As it regulates the intracranial pressure, it also regulates the blood pressure in the brain, allowing the brain’s cells to work more effectively.
The CSF also eliminates waste products and circulates nutrients and filtered chemicals to the brain. It decreases the brain’s weight by 1000 grams by making it buoyant and suspended, allowing it to grow bigger without collapsing because of its weight.
Ventral Cavity
The ventral cavity is at the anterior part (back) of the human body and is composed of 2 divisions: The abdominopelvic cavity and thoracic cavity. The organs found inside this cavity are the heart, lungs, reproductive organs, and intestines. The ventral cavity also contains fluid that protects its organs.
Clinicians divide this cavity into sections called quadrants (upper, lower, left, and right) since the human organs, in reality, are mobile and move their location every time the patient changes position. A method of dividing it into regions can be used as well. These regions are the hypochondriac, epigastric, lumbar, umbilical, iliac, and inguinal and pubic regions.
Abdominopelvic Cavity
This cavity is located on the lower part of the human trunk. It is subdivided into the pelvic and abdominal cavities. The abdomen or abdominal cavity accommodates the digestive organs such as the kidneys, stomach, liver, small intestine, and portions of the large bowel or large intestine. The pelvic cavity accommodates the reproductive organs, including the urinary bladder and the rectum.
The trunk of the human body is an important anatomical area. The abdominal wall entirely protects it. This cavity is surrounded by fascias and muscles, making it flexible to reshape with the viscera inside it.
Thoracic cavity
The thoracic cavity is located directly under the ribcage. It is separated into chambers: left pleural cavity, right pleural cavity, and mediastinum. This cavity encases and protects the respiratory, cardiovascular, and lymphatic organs, including the heart and lungs.
The cavity is protected by the thoracic wall and has a top and bottom thoracic aperture known as the thoracic outlet and inferior thoracic inlet.
Functions of the Ventral Cavity
Ventral Cavity has three serous membranes filled with fluid that gives lubrication for the organs’ movement. They are the pleura, pericardium, and peritoneum.
Pleura: is the serous membrane that outlines the pleural cavity. It plays an important role in the respiratory tract. It cushions the lungs to reduce friction from the chest cavity and rib cage. It is composed of a double-layered membrane that encloses each lung. A minimal amount of pleural fluid separates these layers from each other.
Pericardium: is the serous membrane lining of the pericardial cavity. It covers the middle part of the thoracic cavity, including the heart and roots of the great vessels.
Peritoneum: a serous membrane that lines the peritoneal cavity. It covers the entire coelom organs. It also provides a pathway for the blood vessels and the lymph to travel to and fro the viscera.
Like other body cavities, ventral cavities are also responsible for housing and protecting the organs inside them from outside trauma and shock. The spaces and fluids inside it that surround the organs absorb the impacts that we may experience.
The cavity also can change shape, allowing certain organs to expand, such as lungs, heart, uterus, and stomach, to do their job and function well without disturbing nearby organs or destroying the tissues around them.
